High pressure fittings for hydraulic applications are known. In some applications having vibratory operational environments, for example, fittings used on internal combustion engines, the known fittings are prone to failure due to fractures and sealing issues. Standard hydraulic fitting designs for hydraulic systems are often not adequate for use on diesel engines due to special high loading conditions encountered only on diesel engines. Examples of known fittings can be found in standards maintained by the Society of Automotive Engineers (SAE). For example, fittings conforming to the SAE J-2244 standard may fail due to exposure of the threads to high pressure oil. Fittings conforming to the SAE J-2337 standard may fail due to high loads imparted to the fitting from engine vibrations, hose connections, hose loads, and hydraulic pressures.
Methods used in the past to improve performance of fittings include use of high strength materials and/or design features such as fillets intended to reduce or eliminate stress risers. One example of a high pressure fitting may also be found in U.S. Pat. No. 5,110,160 by Brozovic, published on May 5, 1992, the contents of which are incorporated herein in their entirety by reference. Another example is a fitting design that conforms to the SAE J-2337 standard. Such fittings are partially effective in withstanding operation on a diesel engine environment, but are complex and costly.
Accordingly, there is a need for a design for a high pressure hydraulic fitting that is not prone to the failures experienced by the known designs, and is simple and cost effective.